Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the readOnly/openWorld/idempotent annotations: it discloses billing ($0.002 per call, free on failure), the failure modes that produce no charge, HTML-to-Markdown cleaning behavior, and PDF-to-text handling. This is the kind of cost and side-effect context an agent needs before invoking a paid open-world call.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three dense sentences with no filler: capability first, then exclusions, then cost. Every clause carries actionable information for the agent.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description does the work of describing returns (Markdown body, title, description, links list, PDF text) and covers cost and failure modes. The one meaningful gap is truncation behavior for `max_characters`, which affects how the agent should interpret partial reads.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 33% (only `links` is described in the schema), so the description carries more burden than usual. It covers the links output and content extraction, but says nothing about `max_characters` — no mention of truncation, defaults, or what happens when content exceeds the cap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb + resource: 'Fetch one public page and get its main content as clean Markdown', plus explicit note that navigation/ads are stripped and that title, description and links are returned. It is clearly distinguishable from web_search (search vs. single-page fetch) in the sibling list.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly enumerates the cases where it cannot be used (JavaScript-rendered pages, login-walled pages, robots.txt-blocked pages) and notes those attempts cost nothing, which directly informs when to attempt a read. It does not name web_search as the alternative for discovery-style tasks, so routing guidance is clear but not complete.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.